Polymerization of a single protein of the pathogen Yersinia enterocolitica into needles punctures eukaryotic cells

E. Hoiczyk, G. Blobel

Research output: Contribution to journalArticle


A number of pathogenic, Gram-negative bacteria are able to secrete specific proteins across three membranes: the inner and outer bacterial membrane and the eukaryotic plasma membrane. In the pathogen Yersinia enterocolitica, the primary structure of the secreted proteins as well as of the components of the secretion machinery, both plasmid-encoded, is known. However, the mechanism of protein translocation is largely unknown. Here we show that Y. enterocolitica polymerizes a 6-kDa protein of the secretion machinery into needles that are able to puncture the eukaryotic plasma membrane. These needles form a conduit for the transport of specific proteins from the bacterial to the eukaryotic cytoplasm, where they exert their cytotoxic activity. In negatively stained electron micrographs, the isolated needles were 60-80 nm long and 6-7 nm wide and contained a hollow center of about 2 nm. Our data indicate that it is the polymerization of the 6-kDa protein into these needles that provides the force to perforate the eukaryotic plasma membrane.

Original languageEnglish (US)
Pages (from-to)4669-4674
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
StatePublished - Apr 10 2001
Externally publishedYes



  • Bacterial pathogenicity
  • Cell contact assays
  • Electron microscopy
  • Protein translocation

ASJC Scopus subject areas

  • Genetics
  • General

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